Urinary and fecal incontinence (UI, FI) after first childbirth is a significant, yet underreported, problem. A recent large prospective cohort trial of primiparous women revealed a prevalence of UI of approximately 33.5% and of FI in approximately 17% of women at six months postpartum. Often these women do not seek care. FI and UI are more common in patients with internal anal sphincter defects and levator muscle tears, but it is unknown whether anatomical findings on postpartum pelvic imaging are directly attributable to birth trauma. No within-patient pelvic magnetic resonance imaging (MRI) studies have been performed in nulliparous women to define the range of normal variability of pelvic floor anatomic findings with comparison to their postpartum MRI findings and symptoms. Moreover, no dynamic pelvic MRI studies have been performed in these patients with 3T high field strength MRI imaging. The specific aims of this study are to prospectively characterize dynamic pelvic 3T MRI findings in healthy nulliparous women and to determine whether new MRI findings are detected after first vaginal or cesarean delivery. We also plan to correlate 3T MRI anal sphincter findings, levator soft tissue findings, and characteristics of the bony pelvis with postpartum pelvic floor symptoms in short-term follow-up. The study will recruit 54 subjects who are seeking reproductive assistance at the reproductive endocrinology and infertility program at UAB. Subjects will be nulliparous women with no baseline symptoms of urinary or fecal incontinence. Subjects will be asked to undergo a prepregnancy MRI and 6-month postpartum MRI study using dynamic techniques and measurements based on a prior NICHD protocol. Measurements of osseous and soft tissue MRI data will be obtained from the images at rest and during strain. The use of 3T MRI is selected to improve image resolution beyond previous reported studies. Measurement of change in pelvic floor parameters will be based upon review of dynamic sagittal images, including cine during evacuation. Validated instruments will be utilized to characterize pelvic floor symptoms at baseline and 6 months postpartum. This study will characterize within-patient interval anatomic pelvic floor changes utilizing 3T MRI after childbirth in primiparous women. A second goal is to determine if these interval changes correlate with pelvic floor symptoms in the short term. PUBLIC HEALTH RELEVANCE: This trial will fill a key gap in the existing literature regarding the development of pelvic floor defects that are directly attributable to pregnancy and childbirth and associated with pelvic floor disorders, including incontinence and prolapse through the use of 3T MRI imaging pre-pregnancy and 6 months postpartum. With the existing experience gained from work with the NICHD Pelvic Floor Disorders Network, this trial will improve the anatomic understanding of the effects of pregnancy and childbirth on pelvic structures by direct measurement of within-patient changes and correlation with development of symptoms. The use of 3T MRI is a novel approach for pelvic floor imaging and the higher resolution may provide valuable new data regarding the structural changes that occur during pregnancy and childbirth.